The ratio of the lengths of the index finger to the ring finger is called the 2D:4D ratio or digit ratio. The 2D:4D ratio of an individual is affected by exposure to androgens (gonadal hormones) e.g., testosterone or estrogen, while in the uterus. As such, the 2D:4D ratio has been suggested as an index for these two hormones which are associated with multiple human traits, phenotypes and conditions.
Hormones are chemicals released by cells which bring about intriguing biological connections because they affect the response of cells in other parts of an organism. As such, there has been an extensive amount of scientific research conducted on the 2D:4D ratio as an index for multiple human traits, phenotypes and conditions. Several studies have now shown that the 2D:4D ratio may correlate with and reveal variation of several human and non-human primate traits such as behavior, vocation, sensory, perception (taste, music), health (food preferences, hormonal related diseases), sexuality, dating and differential psychology (ability, cognition, and personality). The most well-know index for the 2D:4D ratio relates to differences between the sexes, it is on average lower in men than in women. Thus, the 2D:4D ratios has several applications in the business and medical fields and provides a non-invasive, simple and time-saving measure screening of multiple human traits, phenotypes and conditions.
Currently, the calculation of the 2D:4D ratio requires that the full length of both index finger and ring finger of the right hand be measured separately by using either a ruler or caliper. Then, the individual divides the length of the index finger by that length of the ring finger. The quotient 2D:4D is the digit ratio. Next, the individual searches the literature for the hormonal status e.g., gonadal hormone exposure index (testosterone or estrogen) that corresponds to his or her 2D:4D ratio. Any 2D:4D ratio smaller than 1 indicates a longer ring finger and is associated with exposure to testosterone, while a ratio larger than 1 indicates a longer index finger and is linked to exposure to estrogen. The problem with this process is that it is time-consuming and the operation (division) is error-prone when done on paper.
Slide rulers have been in use for a long time but some slide rules are extremely specialized for very narrow applications. An example of a slide ruler that solves a specific problem is a slide ruler to estimate the Body Mass Weight of an individual from its measurements of weight and height as described or disclosed by U.S. Patent Publication No. 2008/0234552 published Sep. 25, 2008 to Averbach.
In view of the above, a need remains for a unique device providing an almost instantaneous calculation of an individual's 2D:4D ratio and simultaneous visualization of corresponding hormonal status. Another need is that such device can be manually manipulated solely by the individual. Yet another need is that the device should be such that it can be used on a continued basis because the range of traits and conditions related to the 2D:4D ratio expands as scientific research develops. Still another need, requires that such device be simple, easy and affordable. Thus, a device solving the aforementioned problems is desired. The present invention is directed to fulfilling these needs.